By Marcello Cherchi, MD PhD
For clinicians
Here we use the term “spontaneous nystagmus” to refer to nystagmus that occurs when an individual is seated upright in the dark, attempting to stare straight ahead. The literature reports a fairly broad range of spontaneous nystagmus in healthy subjects, which in turn raises questions about the diagnostic utility of this finding.
Hajioff and colleagues (Hajioff et al. 2000) studied 96 healthy subjects (56 men) age 66 – 89 years (median age 76 years) using electronystagmography. They reported that 5 out of 96 subjects (5.2%) exhibited spontaneous nystagmus while sitting upright in darkness.
Geisler and colleagues (Baba et al. 2004) studied 30 healthy subjects age 20 – 78 with videonystagmography and found 2 (6.6%) exhibited spontaneous nystagmus.
Takahashi and colleagues (Takahashi, Kitamura, Miyata 1996) examined 30 healthy subjects using electronystagmography. They found that 5 (16.7%) subjects exhibited spontaneous nystagmus.
Levo at al.(Levo, Aalto, Petteri Hirvonen 2004) studied 20 healthy subjects using videonystagmography. They reported that spontaneous nystagmus was observed in 20% of individuals while sitting upright in darkness.
Vesterhauge and colleagues (Vesterhauge and Kildegaard Larsen 1977) studied 50 healthy subjects (25 male) with electronystagmography. They reported that 15 (30%) exhibited spontaneous horizontal nystagmus ranging in amplitude from 1.2 – 8.2 deg/sec, though of those fifteen individuals, only one had nystagmus of an amplitude of 8.2 deg/sec; the remaining 14 had an amplitude of 1.2 – 5.0 deg/sec. This same study examined a different subset of 15 patients a second time (24 hours later) and found that 12 (24%) had no spontaneous nystagmus on either the first or second examination; 2 (13.3%) had nystagmus on the first examination but not on the second; none had nystagmus on the second but not the first examination; and 1 (6.6%) had nystagmus on both the first and second examinations; this emphasizes that spontaneous nystagmus can be variable in one and the same healthy subject.
Bisdorff and colleagues (Bisdorff et al. 2000) studied 40 healthy subjects (20 males) age 21 – 55 years using videonystagmography. They reported that 16 of 40 subjects (40%) exhibited spontaneous vertical nystagmus while upright in darkness; of these, 4 exhibited downbeat nystagmus (0.7±0.27 deg/sec) and 12 exhibited upbeat nystagmus (2.58±1.38 deg/sec).
Taken together, these studies appear to show that there is a very broad range of spontaneous nystagmus (5.2% – 40%) among different healthy subjects, and one study even shows differences over time in the same individual. Of the studies that report the amplitude of spontaneous nystagmus in healthy individuals, the magnitude appears relatively small, though there are outliers (e.g., 8.2 deg/sec).
References
Baba S, Fukumoto A, Aoyagi M, Koizumi Y, Ikezono T, Yagi T (2004) A comparative study on the observation of spontaneous nystagmus with Frenzel glasses and an infrared CCD camera. J Nippon Med Sch 71: 25-9.
Bisdorff AR, Sancovic S, Debatisse D, Bentley C, Gresty MA, Bronstein AM (2000) Positional nystagmus in the dark in normal subjects. Neuro-Ophthalmology 24: 283-290. doi: 10.1076/0165-8107(200008)2411-VFT283
Hajioff D, Barr-Hamilton RM, Colledge NR, Lewis SJ, Wilson JA (2000) Re-evaluation of normative electronystagmography data in healthy ageing. Clin Otolaryngol Allied Sci 25: 249-52. doi: coa361 [pii]
Levo H, Aalto H, Petteri Hirvonen T (2004) Nystagmus measured with video-oculography: methodological aspects and normative data. ORL J Otorhinolaryngol Relat Spec 66: 101-4. doi: 10.1159/000079327
Takahashi J, Kitamura K, Miyata M (1996) Spontaneous nystagmus in normal subjects. ORL J Otorhinolaryngol Relat Spec 58: 42-5. doi: 10.1159/000276794
Vesterhauge S, Kildegaard Larsen P (1977) Normal values in a routine ENG test. Acta Otolaryngol 84: 91-7. doi: 10.3109/00016487709123946
